While I'm sure both Gasols would love to play for Barcelona if there's a lockout, I'm just not sure if Barcelona should do it.
Sure, the team would get better, but what would happen the following season? The Gasol brothers would leave, and Barcelona's frontcourt would be really thin (it's not like they can keep on the injured list the players that would replaced by Pau and Marc).
Barcelona is a top candidate to win every FIBA trophy as it is, so why risk their future?

Players they need = Pau

Players they don't need at all = Marc and Calderon

They are weak at power forward, having just Wallace behind Lorbek. They could really use Pau. They don't need the other two guys at all though.